Robotic End Effector with Dorsally Supported Actuation Mechanism

ABSTRACT

A robotic end-effector to provide an anthropomorphic hand with a dorsal actuation system. The hand has a substantially planar palm and fingers extending from the palm and capable of flexion and extension relative to the palm. The dorsal actuation system is supported on the palm and fingers, with actuators positioned at a dorsal side of the palm and links positioned at a dorsal side of the fingers.

BACKGROUND

Robotic hands or grippers typically require numerous degrees of freedomand elaborate control methodologies to compete with the versatility andeffectiveness of the human hand. Robotic hands have been developed togenerate high grasping forces by providing remote actuation, Independentactuation of every finger joint can lead to designs that are bulky,fragile and complicated. The development of robotic hands or grippers isan ongoing endeavor.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the invention will be apparent from thedetailed description which follows, taken in conjunction with theaccompanying drawings, which together illustrate, by way of example,features of the invention; and, wherein:

FIG. 1a is a front perspective view of a robotic end-effector, namely asemi-anthropomorphic hand, with a dorsal actuation system in accordancewith an example.

FIG. 1b is a rear perspective view of the robotic end-effector of FIG. 1a.

FIG. 2a is a side view of the robotic end-effector of FIG. 1 a.

FIG. 2b is an opposite side view of the robotic end-effector of FIG. 1a.

FIG. 3 is a front view of the robotic end-effector of FIG. 1 a.

FIG. 4 is a top or dorsal view of the robotic end-effector of FIG. 1 a.

FIG. 5 is a bottom or palmar view of the robotic end-effector of FIG. 1a,

FIG. 6 is an end view of the robotic end-effector of FIG. 1 a.

FIG. 7 is a side view of the robotic end-effector of FIG. 1a , shownwith the other fingers and thumb removed to show a single finger, namelyan index finger.

FIG. 8 is a side view of the index finger and associated dorsal actuatorof the robotic end-effector of FIG. 1 a.

FIGS. 9a-c are perspective views of the robotic end-effector of FIG. 1a, shown with the fingers and associated dorsal actuators removed to showthe thumb.

FIG. 10 is a side view of the robotic end-effector of FIG. 1a , shownwith a guard over the dorsal actuation system.

FIG. 11 is a tope view of robotic end-effector of FIG. 1a , shown withthe guard over the dorsal actuation system.

FIG. 12a is a schematic side view of a robotic end-effector inaccordance with an example, showing the fingers in partial flexion aboutan object.

FIG. 12b is a schematic side view of the robotic end-effector of FIG.12a , showing the fingers in flexion about the object.

FIG. 13a is a schematic side view of the robotic end-effector inaccordance with an example, showing the fingers in extension.

FIG. 13b is a schematic side view of the robotic end-effector of FIG.13a , showing the fingers in partial flexion about an object.

FIG. 13c is a schematic side view of the robotic end-effector of FIG.13a , showing the fingers in flexion about an object.

FIG. 14 is a perspective view photograph of a robotic end-effector,namely a semi-anthropomorphic hand, with a dorsal actuation system inaccordance with an example.

Actuators of the dorsal actuation system in FIGS. 1a -11 are shown intransparency.

Reference will now be made to the exemplary embodiments illustrated, andspecific language will be used herein to describe the same. It willnevertheless be understood that no limitation of the scope of theinvention is thereby intended.

DETAILED DESCRIPTION

As used herein, the term “substantially” refers to the complete ornearly complete extent or degree of an action, characteristic, property,state, structure, item, or result. For example, an object that is“substantially” enclosed would mean that the object is either completelyenclosed or nearly completely enclosed. The exact allowable degree ofdeviation from absolute completeness may in some cases depend on thespecific context. However, generally speaking the nearness of completionwill be so as to have the same overall result as if absolute and totalcompletion were obtained. The use of “substantially” is equallyapplicable when used in a negative connotation to refer to the completeor near complete lack of an action, characteristic, property, state,structure, item, or result.

As used herein, “adjacent” refers to the proximity of two structures orelements. Particularly, elements that are identified as being “adjacent”may be either abutting or connected. Such elements may also be near orclose to each other without necessarily contacting each other. The exactdegree of proximity may in some cases depend on the specific context.

As used herein, “planar” refers to being substantially planar althoughthe planar item can have a relatively small degree of curvature becauseit is more planar than curved. For example, a palm can be described asplanar even though it has a concave curvature, and the palm is moreplanar than curved. In addition, “straight” refers to beingsubstantially straight although the item may be slightly curved, becausethe item is more straight than curved. For example, a finger inextension is straight relative to the curvature of the finger inflexion. In addition, “parallel” refers to being substantially planaralthough there may be a small angular deviation from perfectly parallelbecause it is more parallel than perpendicular or orthogonal. Forexample, the fingers of a hand can be substantially parallel with thepalm when the fingers are in extension even though the fingers can besomewhat arcuate and somewhat transvers to the palm.

An initial overview of technology embodiments is provided below and thenspecific technology embodiments are described in further detail later.This initial summary is intended to aid readers in understanding thetechnology more quickly but is not intended to identify key features oressential features of the technology nor is it intended to limit thescope of the claimed subject matter.

Disclosed herein is a robotic end-effector with an anthropomorphic handand a dorsal actuation system supported on a palm of the hand andpositioned at a dorsal side of the palm and the fingers. The hand can beanthropomorphic or semi-anthropomorphic, with a palm, at least threefingers and a thumb. Thus, the end-effector or hand can be utilized withstandard items, such as tools, or standard interfaces, such as doorhandles. Positioning the actuation system on the hand allows theend-effector or hand to be modular and easily coupleable to a roboticarm. In addition, positioning the actuation system on the hand allows adirect drive of the hand, or fingers and thumb, as opposed to beingremote or driven by a remote drive. Furthermore, positioning theactuation system on the hand allows separate and direct actuation thefingers and thumb. In addition, the actuation system can move thefingers and the thumb in flexion from proximal to distal phalangesaround an object with a wrap grasp (proximal to distal phalanges) like anatural hand. In addition, each finger and thumb can utilize a singleactuator. Furthermore, the actuation system can provide a substantialgrip.

In addition the end-effector or hand can utilize under-actuated fingersto provide low actuator count and a high degree of conformal graspingfor simple objects and tasks, without the need for numerous degrees offreedom or elaborate control methodologies. The end-effector or hand canutilize compression multi-bar linkages and offset joint kinematics toprovide high grasping forces around irregularly shaped objects with aslittle as one actuator per finger. In one aspect, the end-effector orhand can have three single-actuator fingers and a two-actuator thumbconfigured into a five degree of freedom, under-actuated hand forhigh-force grasping of a variety of utilitarian objects. In one aspect,degree of freedom reduction is accomplished through the use of a singleactuator to drive serially-connected four-bar linkages within amulti-segment finger. This allows for grasping objects of arbitraryshape. The finger segment lengths and bell crank heights or radii can betailored to meet the desired contact force distribution around suchobjects. The use of compression linkages provides a grasping forcewithout the use of tendons and pulleys on the underside of the finger,thereby minimizing bulk on the working side of the hand and overallmagnitude of actuator force (reduced actuation force leads to lessreaction forces within the finger joints, compared with tendon actuationwithin the finger profile). The space available on the back of the handcan provide adequate space for larger actuators that “stick out” beyondthe envelope of the human hand, so that large forces can be exertedwithout interfering with the portions of the hand that interact withobjects.

The contact force distribution for extra-small or extra-large curvaturescan be further tailored using application-specific drive link lengths,when necessary. In addition, the hand can utilize a set of splayedfinger root joints so that large objects fit (or are captured) when thefingers are extended, and small objects fit (or are captured) when thefingers are closed. Moreover, using parallel but offset individualfinger segment hinges, the hand can assume a natural grasp around longcylindrical shapes (such as hammer handles, ladder rungs, ropes andcables). The offset hinges can also allow the fingers to wrap tighterwithout collision between distal finger segments.

The use of passive spring elements and flexion/extension stops withineach finger segment joint can provide for deterministic fingertrajectories during non-contact actuation. For example, when starting tograsp an object, it is desirable to have a fully extended finger firstbend at the most proximal joint. The second joint can then bend,followed by the final (most distal) joint. Likewise, when releasing anobject, it is desirable to reverse this sequence. The spring stiffnesswithin each finger joint is sized specific to thekinematically-determined torque delivery at each location (note that themagnitude of torque resistance is minimal compared to the actuationtorque at full grasp). The finger segment stops further preventover-center singularities from occurring during uni-axial segmentloading (e.g., singularities caused by a push force down the length of afinger).

A two degree of freedom thumb provides an under-actuated series offinger segments using one actuator, with an additional actuator providedto rotate the thumb's base orientation (much like the human thumb).Small objects use the thumb rotated into rough alignment with thefingers, while large objects use the thumb rotated away from thefingers. Again it is observed that discarding the constraint to abide bythe envelope of the human hand on the back of the thumb and palm,provides sufficient space to place high strength actuation withoutinterfering with grasping functions.

In a similar way to the thumb, but using a passive spring instead of anactuator, an additional degree of freedom can be added to the base ofthe little finger (or, possibly, to other fingers) to allow more compactfinger nesting when placing the open fingers inside the closed handle ofsome tools.

FIGS. 1a and 1b depict an exemplary end-effector 10 in accordance withan embodiment. The end-effector 10 can have or can be an anthropomorphichand 14. The hand 14 has a palm 18 with a palmar or ventral side 22 anda dorsal side 26. The palm 18 or the palmar side 22 can be flat orplanar, as shown. In another aspect, the palm 18 or the palmar side 22can have a slight curvature or concavity, but is more flat or planarthan curved or concave, as with a natural human palm. The palm 18 canhave a thickness between the palmar and dorsal sides 22 and 26. In oneaspect, the palm 18 can be or can have a frame with an interior space orhollow(s). In one aspect, the palm 18 can be formed of plastic, and canbe formed by injection molding or 3D printing. In another aspect, thepalm 18 can be formed of metal, and can be formed by machining orcasting.

In addition, the end-effector 10 and the hand 14 have at least threefingers 30, 32 and 34, including for example, a first or index finger30, a second or middle finger 32, and a third, ring or pinky finger 34.The fingers 30, 32 and 34 are pivotally coupled to the palm 18. Thefingers 30, 32 and 34 pivot between extension (straight and/or away fromthe palm 18) and flexion (curved and/or towards the palm 18), or anextended position and a flexed position. In extension, the fingers 30,32 and 34 can extend away from the palm 18 or the palmar side 22. Inflexion, the fingers 30, 32 and 34 can be arcuate, and can be positionedso as to oppose the palmar side 22 of the palm 18. The fingers 30, 32and 34 will be discussed in greater detail below with respect to finger30 and FIGS. 7 and 8. The terms “flexion” or “flex” and “extend” or“extension” as used herein are intended to comprise the same or asimilar meaning as understood by those skilled in the art as theypertain to the human hand.

In addition, the end-effector 10 and the hand 14 has a thumb 38pivotally coupled to the palm 18. The thumb 38 can pivot betweenabduction (away from and/or opposing the fingers 30, 32 and 34) andadduction (toward and/or with the fingers 30, 32 and 34). In abduction,the thumb 38 can be transvers to the palm 18. In adduction, the thumb 38can be straightened, such as to be planar with the palm 18. In addition,the thumb 38 can be pivotal between extension and flexion. In extension,the thumb 38 can be straightened. In flexion, the thumb 38 can bearcuate. The thumb 38 is described below in greater detail and withrespect to FIGS. 9a -9 c.

FIGS. 2a and 2b depict the fingers 30, 32 and 34 of the end-effector 10or the hand 14 in extension. Even in extension, the fingers 30, 32 and34, or the phalanges thereof, can have a slight curvature and anglebetween adjacent phalanges, while still being substantially straight.For example, in extension, adjacent phalanges can have an acute angleless than 30 degrees in one aspect, less than 25 degrees in anotheraspect, and less than 20 degrees in another aspect. In addition, FIGS.2a and 2b depict the thumb 38 is in abduction, transverse with the palm,and in extension.

FIGS. 3 and 4 depict the fingers 30, 32 and 34 of the end-effector 10 orthe hand 14 arrayed at acute angles with respect to one another. Inaddition, the end-effector 10 and the hand 14 has a dorsal actuationsystem 42 for actuating the fingers 30, 32 and 34 and the thumb 38. Theactuation system 42 can be supported on the dorsal side 26 of the palm18 or the hand 14, and the dorsal side of the fingers 30, 32 and 34 andthe thumb 38. The actuation system 42 can comprise a single actuator 46for each finger 30, 32 and 34, and a pair of actuators for the thumb 38,namely first and second actuators 50 and 52. The actuators 46, 50 and 52can be disposed on the dorsal side 26 of the palm 18, or the back of thehand 14. In one aspect, some of the actuators 46 can be disposed in, orpartially disposed in, the hand 14 or the frame of the palm 18. Inanother aspect, some of the actuators 50 and 52 can be disposed outsideof an envelope of the hand 14, and/or disposed outside an envelope of anatural hand, and/or outside the frame of the palm 18. The actuators 46,50 and 52 can comprise pneumatic cylinders, hydraulic cylinders, linearelectric motors, rotation motors, voice coils, or the like. In addition,the actuation system 42 comprises links, bell cranks, and yokes,supported on the fingers 30, 32 and 34 and the thumb 38, as described ingreater detail below and with respect to FIGS. 7-9 c.

The hand 14 or the palm 18 can have a thickness and can comprise a frameas mentioned above. The frame can have a skeleton with interior cavitiesor hollows to receive all or part of the actuators 46. In addition, thepalm 18 or the palmar side 22 thereof can have a plate coupled to theframe to close the interior cavities or hollows with respect to thepalmar side 22. In one aspect, the actuators 46 can be disposed in thethickness of the palm 18 to protect the actuators 46. In another aspect,the actuators 46 can extend beyond a thickness of the palm 18 andoutside an envelope of a natural hand to facilitate actuation of thefingers 30, 32 and 34.

FIGS. 5 and 6 (and FIG. 1b ) depict the end-effector 10 or the hand 14with a releasable end-effector to robotic arm attachment interface 56(hereinafter releasable attachment interface 56) at a proximal end(i.e., that end of the end-effector opposite the fingers and the enddesigned, configured and intended to couple to a robotic arm) of thepalm 18 of the hand 14 of the end-effector 10. The releasable attachmentinterface 56 can releasably attach the robotic end-effector 10 or thehand 14 to a robotic arm (not shown). Because the dorsal actuationsystem 42 is supported on the dorsal side 26 of the hand 14 or the palm18, in some examples the releasable attachment interface 56 can connectto a robotic arm without an actuator or actuator link, such as cables,rods or belts, spanning across the attachment interface. However, otherexamples may utilize or be operable with an actuator in connection witha wrist-like joint between the end-effector 10 and the robotic arm. Inaddition, the end-effector 10 or the hand 14 with the releasableattachment interface 56 can define a modular robotic end-effector thatcan be more easily attached, removed, and/or swapped with respect to therobotic arm. Flexible lines associated with the actuators, such aspneumatic hoses, hydraulic hoses, power cords, sensor wires, etc., canextend across the attachment interface: but such flexible lines are moreeasily coupled and uncoupled than actuator links, such as tensionedcables, rods and belts. Thus, in one aspect, all actuation of the atleast three fingers 30, 32 and 34 and the thumb 38 can be supported onthe robotic end-effector 10 or the hand 14, including all actuators andall links coupled to the at least three fingers 30, 32 and 34 and thethumb 38. In one example, the releasable attachment interface 56 cancomprise mating stubs extending from the proximal end of the palm 18 ofthe hand 14 of the end-effector 10 that can align and mate withcorresponding notches in the robotic arm, or vice versa. Of course, thisis just one example. Those skilled in the art will recognize a varietyof other ways the connecting or attachment interface between the roboticend-effector 10 and a corresponding robotic arm could be designed, andthe individual mating end-effector 10 and robotic arm configured toprovide the desired interface.

FIGS. 7 and 8 depict an exemplary finger 30 of the hand 14 or theend-effector 10; and will be utilized to describe the other fingers 32and 34, and even the thumb 38, with the understanding that a descriptionof finger 30 applies to the other fingers 32 and 34, and the thumb 38,as well. In addition, FIGS. 7 and 8 depict the dorsal actuation system42; and will be utilized to describe the actuation system 42 for theother fingers 32 and 34, and even the thumb 38, with the understandingthat a description of the dorsal actuation system 42 for the finger 30applies to the other fingers 32 and 34, and the thumb 38, as well. FIG.7 depicts the finger 30 pivotally coupled to the palm 18 of the hand 14,with the other fingers, the thumb, and the other actuators removed forclarity. The finger 30 is shown in extension with respect to the palmarside 22 of the palm 18. FIG. 8 depicts the finger 30 along with theactuation system 42, but with the palm, the other fingers, and the thumbremoved for clarity.

The finger 30 comprises phalanges pivotally coupled together in series.In one aspect, the finger 30 comprises at least two phalanges. Inanother aspect, the finger can comprise three phalanges, as shown inFIGS. 12a -14. The finger 30 comprises a proximal phalanx 72 pivotallycoupled to the palm 18 at a metacarpo-phalangeal joint or pivot 76. Thepalm 18 can have a yoke 80 (FIGS. 5 and 7) in which the proximal phalanx72 can be pivotally coupled, and which can carry a pivot axle of themetacarpo-phalangeal joint 76. The finger 30 also comprises a distalphalanx 84 pivotal with respect to the proximal phalanx 72 and pivotalabout a distal joint or pivot 88. In one aspect, the distal phalanx 84can be pivotally coupled to the proximal phalanx 72, as shown. Inanother aspect, the finger can have an intermediate phalanx coupledbetween the proximal and distal phalanges, as shown in FIGS. 12a -14. Aswith the palm 18, the finger 30 has a ventral side and a dorsal side,also represented by 22 and 26, respectively. The finger 30, or theproximal and distal phalanges 72 and 84 thereof, can be formed ofplastic, and can be formed by injection molding or 3D printing. Inanother aspect, the finger 30, or the proximal and distal phalanges 72and 84 thereof, can be formed of metal, and can be formed by machiningor casting.

As indicated above, the dorsal actuation system 42 also comprises linksand bell cranks, and even a yoke for the thumb 38, in addition to theactuator 46. As described above, the actuation system 42 comprises theactuator 46 supported on the palm 18, and positioned on the dorsal side26 of the palm 18. The actuation system 42 also comprises a proximalbell crank 92 pivotally coupled to the palm 18 along with the proximalphalanx 72 at the metacarpo-phalangeal joint 76. Thus, the proximal bellcrank 92 pivots about the metacarpo-phalangeal joint 76 along with theproximal phalanx 72. A proximal dorsal link 96 is pivotally coupledbetween the proximal bell crank 92 and the distal phalanx 84. In oneaspect, the distal phalanx 84 has a protrusion or tab 100 extendingtherefrom at the distal joint 88. The proximal dorsal link 96 can bepivotally coupled to the distal phalanx 84 or the protrusion 100thereof, as shown. In addition, the proximal dorsal link 96 can bepositioned at the dorsal side 26 of the proximal phalanx 72. Inoperation, the actuator 46 extends the proximal bell crank 92 and theproximal dorsal link 96 to pivot the proximal and distal phalanges 72and 84 in flexion, or in the flexion direction to oppose the palmar side22 of the palm 18. In one aspect, the actuator 46 can retract to pivotthe proximal and distal phalanges 72 and 84 in extension. In one aspect,the actuator 46 can be oriented parallel or transverse with the palmaror dorsal side 22 or 26 of the palm 18. In addition, the actuator 46 canbe disposed on or over the dorsal side 26 of the palm 18. Furthermore,the actuator 46 can be disposed at least partially within a frame of thepalm 18.

In another aspect, the proximal and distal phalanges 72 and 84 can bebiased in extension, or can be retracted to extension by springs. Theactuation system 42 can comprise a metacarpo-phalangeal spring 104(FIGS. 5 and 8) coupled to the metacarpo-phalangeal joint 76 to bias theproximal phalanx 72 in extension. Similarly, the actuation system 42 canalso comprise a distal spring 108 (see FIG. 5) coupled to the distaljoint 88 to bias the distal phalanx 84 in extension. The springs 104 and108 can be coil springs circumscribing axles of the joints 76 and 88,respectively.

The lengths or the phalanges 72 and 84 and the height or radius of thebell crank 92 can be tailored to meet the desired contact forcedistribution around an object. The proximal bell crank 92 and/or theproximal dorsal link 96 can be formed of plastic, and can be formed byinjection molding or 3D printing. In another aspect, the proximal bellcrank 92 and/or the proximal dorsal link 96 can be formed of metal, andcan be formed by machining or casting.

In addition, one or more sensors can be positioned on the finger 30and/or the actuator system 42 to determine a position and/or a forceexerted by the finger 30 or the actuator 46. For example, a sensor 112(FIG. 8) can be positioned at a pivot link between the bell crank 92 andthe actuator 46.

Referring again to FIGS. 3 and 4, the proximal dorsal links 96 and theactuators 46 of the actuation systems 42 of the fingers 30, 32 and 34can be parallel with the fingers, but off-set, to accommodate placementof the actuators 46 on the hand 14 or the dorsal side 26 of the palm 18.

FIGS. 9a-9c depict the thumb 38 of the hand 14 or the end-effector 10.In addition, FIGS. 9a-9c depict the dorsal actuation system of the thumb38. FIGS. 9a-9c depict the thumb 38 pivotally coupled to the palm 18 ofthe hand 14, with the other fingers and the other actuators removed forclarity. It is understood that the description of the finger 30 and theactuation system 42 applies equally to the thumb 38. As such, the thumb38 can have a proximal phalanx 72 pivotally coupled to the palm 18 at ametacarpo-phalangeal joint 76, and a distal phalanx 84 pivotal withrespect to the proximal phalanx 72 about a distal joint 88. In addition,the actuation system 42 can have an actuator 50, a proximal bell crank92, a proximal dorsal link 96, and a protrusion 100.

In addition to pivoting between extension and flexion, as do thefingers, the thumb 38 can also be movable or pivotal betweenretroposition (substantially planar or parallel with the palmar side 22of the palm 18) and anteposition (opposing the palmar side 22 of thepalm 18). Thus, the proximal phalanx 72 of the thumb 38 can have a pairof pivots with respect to the palm 18, including a first axis or pivot122 (FIG. 9b ) in which the thumb 38 pivots in flexion/extension, and asecond axis or pivot 126 (FIGS. 9a and 9c ) in which the proximalphalanx 72 of the thumb 38 pivots in abduction/adduction. The first andsecond pivots axes 122 and 126 can be transverse to one another and canintersect. The dorsal actuation system 42 of the thumb 38 can comprise apair of actuators, namely a first actuator 50 to pivot the thumb 38 inflexion/extension about the first axis 122, and a second actuator 52 topivot the thumb 38 in abduction/adduction about the second axis 126.

The thumb 38 can have a yoke 130 pivotally coupled to the palm 18. Theyoke 130 can have a shaft or neck that pivots about the second axis 126.The second actuator 52 can be supported on the dorsal side 26 of thepalm 18 and coupled to the yoke 130 to pivot the yoke about the secondaxis 126. The proximal and distal phalanges 72 and 84 of the thumb 38can be supported on the yoke 130 with the proximal phalanx 72 of thethumb 38 pivotally coupled to the yoke 130. The first actuator 50 can besupported on the yoke 150 and coupled to the proximal phalanx 72 of thethumb 38. In operation, the second actuator 52 pivots the yoke 150, theproximal and distal phalanges 72 and 84 of the thumb 38, and the firstactuator 50, about the second axis 126 in an abduction/adductiondirection between retroposition and anteposition, while the firstactuator 50 pivots the proximal and distal phalanges 72 and 84 of thethumb 38 about the first axis 122 in extension/flexion.

The actuators 46, 50 and 52, or portions thereof, can be disposedoutside of the palm 18, or envelope of a natural human hand. Thus, theactuators 46, 50 and 52 can be positioned as desired or to maximizefinger movement or force.

FIGS. 10 and 11 depict the end-effector 10 and the hand 14 with a guard140 disposed over the dorsal side 26 of the palm 18, and over theactuators 46 and 50 to protect the actuators. The guard 140 isillustrated as transparent.

FIGS. 12a and 12b schematically depict an end-effector 10 b and a hand14 b which are similar in most respects to that described above, andwhich description is hereby incorporated herein where applicable, aswill be recognized by those skilled in the art. The finger 30 bcomprises three phalanges coupled together in sequence. The finger 30 bfurther comprises a middle phalanx 162 pivotally coupled to the proximalphalanx 72 at a proximal joint or pivot 166 and to the distal phalanx 84at the distal joint 88. The dorsal actuation system 42 b comprises amiddle bell crank 170 pivotally coupled to the proximal phalanx 72 atthe proximal joint 166 along with the distal phalanx 84. In addition, amiddle link 174 is pivotally coupled to and between the middle bellcrank 170 and the distal phalanx 84. The middle link 174 is positionedat the dorsal side 26 of the middle phalanx 162.

Each finger 30 b and actuation system 42 b can form a series ofserially-connected four-bar linkages. A proximal four-bar linkage can beformed by the proximal phalanx 72, the proximal bell crank 92, theproximal dorsal link 96, and the middle bell crank 170. Similarly, adistal four-bar linkage can be formed by the middle phalanx 162, themiddle bell crank 170, the middle link 174, and the distal phalanx 162,or the protrusion 100 thereof.

In one aspect, the fingers and the actuation system of the end-effector10 b and a hand 14 b can be sized as shown in Table 1.

TABLE 1 Index Middle Ring Thumb Phalanx Length (in.) Proximal Phalanx1.576 1.995 1.460 1.487 Middle Phalanx 0.974 1.233 0.902 0.919 DistalPhalanx 0.602 0.762 0.558 0.568 Bell Crank Radius (in.) Proximal BellCrank 1.000 1.000 1.000 1.000 Middle Bell Crank 0.500 0.500 0.500 0.500Protrusion 0.191 0.191 0.191 0.191

FIGS. 13a-13c schematically depict an end-effector 10 c and a hand 14 cwhich are similar in most respects to those described above, and whichdescription is hereby incorporated herein where applicable, as will berecognized by those skilled in the art. FIGS. 13a-13c schematicallydepict the end-effector 10 c and the hand 14 c in operation movingbetween extension of the finger 30 c in FIG. 13a and flexion of thefinger 30 c in FIG. 13c . In addition, FIGS. 13a-13c demonstrate a wrapgrasp of the finger 30 c and the actuation system 42 c in which thephalanges and associated links pivot and contact a grasped object insequential order beginning with the proximal phalanx 72, then the middlephalanx 162, and then the distal phalanx 84: or the proximal phalanx 72then the distal phalanx 84 in the case of two phalanges. Furthermore,the palm 18 or the palmar side 22 can have a slight curvature orconcavity, but is more flat or planar than curved or concave, as with anatural human palm.

FIG. 14 is a photograph of an end-effector 10 d and a hand 14 d whichare similar in most respects to those described above, and whichdescription is hereby incorporated herein where applicable, as will berecognized by those skilled in the art.

Although the disclosure may not expressly disclose that some embodimentsor features described herein may be combined with other embodiments orfeatures described herein, this disclosure should be read to describeany such combinations that would be practicable by one of ordinary skillin the art. The user of “or” in this disclosure should be understood tomean non-exclusive or, i.e., “and/or,” unless otherwise indicatedherein.

Reference was made to the examples illustrated in the drawings andspecific language was used herein to describe the same. It willnevertheless be understood that no limitation of the scope of thetechnology is thereby intended. Alterations and further modifications ofthe features illustrated herein and additional applications of theexamples as illustrated herein are to be considered within the scope ofthe description.

Furthermore, the described features, structures, or characteristics maybe combined in any suitable manner in one or more examples. In thepreceding description, numerous specific details were provided, such asexamples of various configurations to provide a thorough understandingof examples of the described technology. It will be recognized, however,that the technology may be practiced without one or more of the specificdetails, or with other methods, components, devices, etc. In otherinstances, well-known structures or operations are not shown ordescribed in detail to avoid obscuring aspects of the technology.

Although the subject matter has been described in language specific tostructural features and/or operations, it is to be understood that thesubject matter defined in the appended claims is not necessarily limitedto the specific features and operations described above. Rather, thespecific features and acts described above are disclosed as exampleforms of implementing the claims. Numerous modifications and alternativearrangements may be devised without departing from the spirit and scopeof the described technology.

While the foregoing examples are illustrative of the principles of thepresent invention in one or more particular applications, it will beapparent to those of ordinary skill in the art that numerousmodifications in form, usage and details of implementation can be madewithout the exercise of inventive faculty, and without departing fromthe principles and concepts of the invention. Accordingly, it is notintended that the invention be limited, except as by the claims setforth below.

What is claimed is:
 1. A robotic end-effector, comprising: ananthropomorphic hand comprising: a palm with a palmar side and a dorsalside; at least three fingers pivotally coupled to the palm and pivotalbetween extension and flexion; and a thumb pivotally coupled to the palmand pivotal between abduction and adduction, and also pivotal betweenextension and flexion; each of the at least three fingers and the thumbcomprising phalanges comprising at least: a proximal phalanx pivotallycoupled to the palm at a metacarpo-phalangeal joint; a distal phalanxpivotally with respect to the proximal phalanx about a distal joint; anda ventral side and a dorsal side; dorsal actuation systems for each ofthe at least three fingers and the thumb, and supported on the dorsalside of the palm and the dorsal sides of the at least three fingers andthe thumb, each dorsal actuation system comprising: an actuatorsupported on the palm and positioned on the dorsal side of the palm; aproximal bell crank pivotally coupled to the palm along with theproximal phalanx; and a proximal dorsal link pivotally coupled betweenthe proximal bell crank and the distal phalanx, and positioned at thedorsal side of the proximal phalanx; and the actuator being operable toextend the proximal bell crank and the proximal dorsal link to pivot theproximal and distal phalanges in flexion.
 2. The robotic end-effector ofclaim 1, wherein all actuation components of the at least three fingersand the thumb are supported on the robotic end-effector including allactuators and all links coupled to the at least three fingers and thethumb.
 3. The robotic end-effector of claim 1, further comprising areleasable attachment interface at a proximal end of the palm configuredto releasably attach the robotic end-effector to a robotic arm, withoutan actuator or actuator link spanning across the attachment interface,and defining a modular robotic end-effector.
 4. The robotic end-effectorof claim 1, wherein the proximal phalanx of the thumb has a pair ofpivots with respect to the palm including a first pivot in which thethumb is operable to pivot in abduction/adduction and a second pivot inwhich the proximal phalanx of the thumb is operable to pivot inflexion/extension.
 5. The robotic end-effector of claim 1, wherein thumbis movable between retroposition and anteposition.
 6. The roboticend-effector of claim 1, wherein the dorsal actuation system of thethumb comprises a pair of actuators.
 7. The robotic end-effector ofclaim 1, wherein the actuator of the thumb is a first actuator operableto pivot the proximal phalanx of the thumb about a first axis; andwherein thumb further comprises: a yoke pivotally coupled to the palm; asecond actuator supported on the dorsal side of the palm and coupled tothe yoke, the second actuator operable to pivot the yoke about a secondaxis; the proximal and distal phalanges of the thumb supported on theyoke with the proximal phalanx of the thumb pivotally coupled to theyoke; the first actuator supported on the yoke and coupled to theproximal phalanx of the thumb; the second actuator operable to pivot theyoke, the proximal and distal phalanges of the thumb, and the firstactuator, about the second axis in an abduction/adduction directionbetween retroposition and anteposition; and the first actuator operableto pivot the proximal and distal phalanges of the thumb about the firstaxis in extension/flexion.
 8. The robotic end-effector of claim 1,wherein each dorsal actuation system further comprises a protrusionextending from the distal phalanx at the distal joint and pivotallycoupled to the proximal dorsal link.
 9. The robotic end-effector ofclaim 1, wherein each dorsal actuation system further comprises ametacarpi-phalangeal spring coupled to the metacarpo-phalangeal jointand biasing the proximal phalanx in extension, and a distal springcoupled to the distal joint and biasing the distal phalanx in extension.10. The robotic end-effector of claim 1, wherein each dorsal actuationsystem for the at least three fingers further comprises the actuatorbeing oriented one of parallel or transverse to the palmar or dorsalside of the palm.
 11. The robotic end-effector of claim 1, wherein eachdorsal actuation system for the at least three fingers further comprisesthe actuator being disposed on or over the dorsal side of the palm. 12.The robotic end-effector of claim 1, wherein each dorsal actuationsystem for the at least three fingers further comprises the actuatorbeing disposed at least partially within a palm frame of the palm. 13.The robotic end-effector of claim 1, wherein each of the at east threefingers further comprises: a middle phalanx pivotally coupled to theproximal phalanx at a proximal joint and to the distal phalanx at thedistal joint; and wherein each of the dorsal actuation systems for theat least three fingers further comprises: a middle bell crank pivotallycoupled to the proximal phalanx at the proximal joint along with thedistal phalanx; and a middle link pivotally coupled to and between themiddle bell crank and the distal phalanx, and positioned at the dorsalside of the middle phalanx.
 14. A robotic end-effector, comprising: ahand comprising: a palm with a palmar side and a dorsal side; at leastthree fingers pivotally coupled to the palm and pivotal betweenextension and flexion; and a thumb pivotally coupled to the palm; thethumb having a first pivot in which the thumb pivots inabduction/adduction; and the thumb having a second pivot in which thethumb pivots in flexion/extension; each of the at least three fingersand the thumb comprising phalanges comprising at least: a proximalphalanx pivotally coupled to the palm at a metacarpo-phalangeal joint; adistal phalanx pivotally with respect to the proximal phalanx at adistal joint; a ventral side and a dorsal side; a metacarpo-phalangealspring coupled to the metacarpo-phalangeal joint and biasing theproximal phalanx in extension; and a distal spring coupled to the distaljoint and biasing the distal phalanx in extension; dorsal actuationsystems for each of the at least three fingers and the thumb, andsupported on the dorsal side of the palm and the dorsal sides of the atleast three fingers and the thumb, each dorsal actuation systemcomprising: an actuator supported on the palm and positioned on thedorsal side of the palm; a proximal bell crank pivotally coupled to thepalm along with the proximal phalanx; a proximal dorsal link pivotallycoupled between the proximal bell crank and the distal phalanx, andpositioned at the dorsal side of the proximal phalanx; and a releasableattachment interface at a proximal end of the palm configured toreleasably attach the robotic end-effector to a robotic arm, without anactuator or actuator link spanning across the attachment interface, anddefining a modular robotic end-effector.
 15. The robotic end-effector ofclaim 14, wherein all actuation of the at least three finger and thethumb is supported on the robotic end-effector including all actuatorsand all links coupled to the at least three fingers and the thumb. 16.The robotic end-effector of claim 14, wherein the proximal phalanx ofthe thumb has a pair of pivots with respect to the palm including afirst pivot in which the thumb pivots in abduction/adduction and asecond pivot in which the proximal phalanx of the thumb pivots inflexion/extension.
 17. The robotic end-effector of claim 14, wherein thethumb is movable between retroposition and anteposition.
 18. The roboticend-effector of claim 14, wherein the dorsal actuation system of thethumb comprises a pair of actuators.
 19. The robotic end-effector ofclaim 14, wherein the actuator of the thumb is a first actuator operableto pivot the proximal phalanx of the thumb about the first axis; andwherein thumb further comprises: a yoke pivotally coupled to the palm; asecond actuator supported on the dorsal side of the palm and coupled tothe yoke, the second actuator operable to pivot the yoke about thesecond axis; the proximal and distal phalanges of the thumb supported onthe yoke with the proximal phalanx of the thumb pivotally coupled to theyoke; the first actuator supported on the yoke and coupled to theproximal link of the thumb; the second actuator operable to pivot theyoke, the proximal and distal phalanges of the thumb, and the firstactuator, about the second axis in an abduction/adduction directionbetween retroposition and anteposition; and the first actuator operableto pivot the proximal and distal phalanges about the first axis in anextension/flexion direction.
 20. The robotic end-effector of claim 14,wherein each dorsal actuation system further comprises a protrusionextending from the distal phalanx at the distal joint and pivotallycoupled to the proximal dorsal link.
 21. The robotic end-effector ofclaim 14, wherein each dorsal actuation system for the at least threefingers further comprises the actuator being oriented one of parallel ortransverse with the palmar or dorsal side of the palm.
 22. The roboticend-effector of claim 14, wherein each dorsal actuation system for theat least three fingers further comprises the actuator being disposed onor over the dorsal side of the palm.
 23. The robotic end-effector ofclaim 14, wherein each dorsal actuation system for the at least threefingers further comprises the actuator being disposed at least partiallywithin the palm.
 24. The robotic end-effector of claim 14, wherein eachof the at least three fingers further comprises: a middle phalanxpivotally coupled to the proximal phalanx at a proximal joint and to thedistal phalanx at the distal joint; and wherein each of the dorsalactuation systems for the at least three fingers further comprises: amiddle bell crank pivotally coupled to the proximal phalanx at theproximal joint along with the distal phalanx; and a middle linkpivotally coupled to and between the middle bell crank and the distalphalanx, and positioned at the dorsal side of the middle phalanx.
 25. Arobotic end-effector, comprising: an anthropomorphic hand with a palmand fingers; and a dorsal actuation system supported on the palm andfingers comprising actuators positioned at a dorsal side of the palm andlinks positioned at a dorsal side of the fingers.
 26. The roboticend-effector of claim 25, further comprising: a thumb pivotally coupledto the palm and pivotal between abduction and adduction, and alsopivotal between extension and flexion.
 27. The robotic end-effector ofclaim 25; further comprising: each of the fingers comprising phalangescomprising at least: a proximal phalanx pivotally coupled to the palm ata metacarpo-phalangeal joint; a distal phalanx pivotal with respect tothe proximal phalanx about a distal joint; and a ventral side and adorsal side; and the dorsal actuation systems for each of the fingerscomprising: a proximal bell crank pivotally coupled to the palm alongwith the proximal phalanx; and a proximal dorsal link pivotally coupledbetween the proximal bell crank and the distal phalanx, and positionedat the dorsal side of the proximal phalanx; and the actuator beingoperable to extend the proximal bell crank and the proximal dorsal linkto pivot the proximal and distal phalanges in flexion.